Just how quickly civil liberties can be eroded is graphically illustrated by our front-page story today. The story lists the host of public authorities which will be able to demand the communication records of every telephone and internet user in the country. Compare this frightening prospect with the picture painted by David Blunkett just a few days before he published his anti-terrorist bill last November. In an article for Tribune, the Labour weekly, setting out the criterion by which he was judging what should be included, the home secretary asserted: "Every measure in our bill has to meet one simple requirement: will it be a practical contribution to combating terrorism." And he gave this pledge: he would not give the police or anyone else the power to routinely monitor phone calls or emails between individuals.

Yet, as we report today, it is not just the police, security services and inland revenue which are to be given an almost complete map of people's private "electronic" lives; data on whom people talk to by email and phone, what websites they consult, and where everyone goes at any particular time while their mobiles are switched on. A long list of other public authorities are being given access too - seven government departments, hundreds of local authorities, all fire authorities and 12 other national bodies, ranging from the atomic energy authority's constabulary to universal service providers as defined under the Postal Services Act of 2000.

Just two years ago ministers tried to turn internet service providers into a supporting arm of the police by a regulation that would have required them to retain internet and email traffic details for 12 months. They were stopped by parliament, which believed this was a step too far. Now, just two years on, this data will be made available not just for anti-terrorist purposes but for criminal investigations and wider purposes too. True, the public authorities will not be able to look at the content of the emails, but the map which they will obtain, particularly with the new generation of mobile phones that pinpoint location to a few metres, makes a mockery of the right to privacy that the Human Rights Act is supposed to protect.

Blanket data retention is the penultimate step towards a national traffic data warehouse, which the security services and police chiefs have been seeking. There are profound civil liberty implications. The web browsing behaviour of a million customers for a year could be held on about 100 matchbox-sized tapes. Ironically, such Orwellian surveillance will be of little help in tracking terrorists or organised crime cells. They can avoid identification by using prepaid mobile phones or web-based email from public terminals. If David Blunkett was being sincere in his Tribune piece, he would drop this catch-all provision. It will not help him catch terrorists, but it will increase public suspicion and mistrust of the security services and the police.

It is time for parliament to step in again. The new powers are being bestowed by a statutory order that is due to be debated in the Commons next Tuesday. It should be resisted by both houses of parliament. It follows a move by the European parliament, revealed 10 days ago in this newspaper, which overturned a decade of data protection by giving member states the power to force internet companies to retain detailed logs of their customers' traffic. Some ministers might want to intervene. Surely Patricia Hewitt, a former general secretary of Liberty, is one who would want to assert the importance of a robust right to privacy?